Variable pulse repetition frequency passively Q-switched laser
AssigneeLockheed Martin Coherent Technologies, Inc.
InventorsJohn Koroshetz, Josef Unternahrer
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Abstract
A passive Q-switch element is disclosed that permits operating a laser with a variable pulse repetition frequency (PRF). The Q-switch comprises two wedges of material, one made from saturable absorber material, the other from transparent material, with the two wedges mounted together to form a constant optical thickness block. By translating the block transversely to a laser beam the amount of saturable absorber material seen by the laser beam is altered and as a result the PRF of the laser is varied.
Claims13
A passive Q-switch element for varying the laser Pulse Repetition Frequency of a laser comprising:
- a first wedge made of saturable absorber material;
- and
- a second wedge made of a non-saturable absorber material;
- wherein the first wedge and the second wedge are sized and assembled to form a discrete, substantially constant optical thickness, block.
A variable PRF Q-switched laser comprising:
- a laser cavity with a gain medium and having a laser cavity axis;
- a passive Q-switch element situated within the laser cavity, for varying the laser Pulse Repetition Frequency of the laser;
- and
- means for translating the Q-switch element in a direction not parallel to the laser axis;
- wherein the Q-switch element is a piece comprising a first wedge made of saturable absorber material and a second wedge made of a non-saturable absorber material, and wherein the first wedge and the second wedge are sized and assembled to form a discrete, substantially constant optical thickness, block.
A Q-switched laser system comprising:
- a laser cavity with a gain medium and having a laser cavity axis;
- a passive Q-switch element situated within the laser cavity, for varying the laser Pulse Repetition Frequency of the laser;
- means for translating the Q-switch element in a direction not parallel to the laser axis;
- wherein the Q-switch element is a piece comprising a first wedge made of saturable absorber material and a second wedge made of a non-saturable absorber material, and wherein the first wedge and the second wedge are sized and assembled to form a discrete, substantially constant optical thickness, block;
- a photo-detector to detect the occurrence of laser pulses;
- a servo control system to compare the pulse repetition frequency of said laser pulses with a predetermined set value;
- and
- an actuator attached to said Q-switch element for moving said Q-switch element in a direction that alters the pulse repetition frequency of the laser to the predetermined set value.
A method for controlling the pulse repetition frequency of a passively Q-switched laser comprising the steps of:
- Q-switching said laser with a Q-switch element including a saturable absorber material of varying optical thickness
- detecting the pulse repetition frequency of said laser;
- comparing said pulse repetition frequency with a preset value;
- and
- translating the Q-switch element such that the optical thickness of saturable absorber material along the laser axis is altered, wherein the PRF of the laser changes to correspond to said preset value.
Dependencies are inferred from the claim text.